:root{
    --theme_color:black;
    --theme_vary_color:white;
    --theme_text_color:white;
    --usual_text_size:16px;
    --usual_title_size:20px;
}
*{
    padding: 0px;
    margin: 0px;
}
ul{
    list-style: none;
}
.com_width{
    width: 1500px;
    margin: auto;
}
@media (max-width:1500px) {
    .com_width{
        width: 100%;
        padding: 0 20px;
        box-sizing: border-box;
    }
}